Lorraine Luk, Eva Dou and Daisuke Wakabayashi of the Wall Street Journal — a publication not known for irresponsibly spreading fact-free rumors — are reporting that Apple is planning to release two new iPhones later this year. They say that one has a display that’s larger than 4 1/2 inches, and the other has one that’s larger than 5 inches — which, if true, will mean that Apple is finally entering the big-screen battle that sucked up all makers of Android phones long ago.

The timing feels about right. It’s the sort of thing Apple might do, but a lot more slowly than people insist it must, and there are surely folks out there who wouldn’t consider today’s 4-inch iPhone 5s or 5c, but would buy one with a roomier display. It would be a way to win back some market share over Android models, particularly from Samsung’s roomy Galaxy S and even roomier Galaxy Note models, which are probably the only iPhone rivals Apple pays much attention to, saleswise.

But there’s a technical issue with larger-screen iPhones, and it has nothing to do with the larger LCD or resized case. Those parts are easy. What’s tricky is rejiggering iOS to accommodate a new screen size. (Unlike Android, iOS isn’t designed to fluidly reconfigure itself for whatever screen size it finds itself on.)

Apple could just put the iPhone’s current 1136-by-640 resolution on a bigger screen of the same aspect ratio, but that would involve bigger pixels and a pixels-per-inch rating lower than the 5s and 5c’s 326ppi. Releasing a new iPhone with less impressive specs seems unlikely, though.

The first and only time that Apple embiggened the iPhone’s screen — with the iPhone 5 in 2012 — it gave the phone a tall-boy 4″ screen, added extra rows of pixels and tweaked iOS 7 allow developers to create alternative screen layouts for the new resolution. The approach worked well, but Apple can’t just replicate it forever, unless it’s O.K. with the iPhone becoming absurdly tall.

Then there’s what Apple did when it gave the iPad a Retina display in 2012: It quadrupled the number of pixels in one fell swoop, so the aspect ratio remained unchanged. That would involve one or more new iPhones with 2672-by-1280 pixels — which sounds nifty to me, but highly unlikely.

So if the iPhone is going to get new screen sizes this year — and it might wind up being available in at least three of them, if the current 4″ version sticks around — it seems probable that Apple will make significant adjustments to iOS to deal with new resolutions.

The first public disclosures about iOS 8 are likely to come at Apple’s WWDC developer confab, traditionally held in the summer. If we learn then, or sometime thereafter, that iOS is dealing with resolution in a new way, bigger iPhones are a done deal. And if there’s no news relating to resolution — well, I’ll be even more curious than usual to see what happens when new iPhones are announced later in the year.